Factors Affecting Median Cable Barrier Crash Frequency: New Insights

Abstract

This study evaluated the impact of roadway cross-sectional and geometric features, traffic characteristics, and median cable barrier placement to the frequency of median-related crashes through statistical modeling using multiyear data. A unique aspect of the model specification was the inclusion of median cable barrier placement data, horizontal curve data, and differential elevation of opposite travel lanes. Negative binomial model was used in linearizing and quantifying these factors with respect to median crossover crash frequency. The variables that were found to significantly influence the frequency of median crashes include the number of lanes, differential elevation, and cable barrier offset from the inside shoulder. Increasing traffic volume was found to increase the frequency of median barrier crashes as well as the presence of curves on a median barrier section was found to increase the frequency of crashes. Higher differential elevation between opposite travel lanes was also found to increase the frequency of median barrier crashes. Increasing the median barrier offset from the inside shoulder of the travel way decreases median barrier injury and fatal crash frequency. Segments with a higher number of lanes and a wider median width were associated with low crash frequencies.